/* $OpenBSD: a_utf8.c,v 1.8 2014/07/11 08:44:47 jsing Exp $ */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 *

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 *

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 *

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */

#include <stdio.h>

#include <openssl/asn1.h>

#include "asn1_locl.h"

/* UTF8 utilities */

/*

 * This parses a UTF8 string one character at a time. It is passed a pointer

 * to the string and the length of the string. It sets 'value' to the value of

 * the current character. It returns the number of characters read or a

 * negative error code:

 * -1 = string too short

 * -2 = illegal character

 * -3 = subsequent characters not of the form 10xxxxxx

 * -4 = character encoded incorrectly (not minimal length).

 */

int

UTF8_getc(const unsigned char *str, int len, unsigned long *val)

{

  const unsigned char *p;

  unsigned long value;

  int ret;

  if (len <= 0)

    return 0;

  p = str;

  /* Check syntax and work out the encoded value (if correct) */

  if ((*p & 0x80) == 0) {

    value = *p++ & 0x7f;

    ret = 1;

  } else if ((*p & 0xe0) == 0xc0) {

    if (*p < 0xc2)

      return -2;

    if (len < 2)

      return -1;

    if ((p[1] & 0xc0) != 0x80)

      return -3;

    value = (*p++ & 0x1f) << 6;

    value |= *p++ & 0x3f;

    if (value < 0x80)

      return -4;

    ret = 2;

  } else if ((*p & 0xf0) == 0xe0) {

    if (len < 3)

      return -1;

    if (((p[1] & 0xc0) != 0x80) ||

        ((p[2] & 0xc0) != 0x80))

      return -3;

    value = (*p++ & 0xf) << 12;

    value |= (*p++ & 0x3f) << 6;

    value |= *p++ & 0x3f;

    if (value < 0x800)

      return -4;

    /* surrogate pair code points are not valid */

    if (value >= 0xd800 && value < 0xe000)

      return -2;

    ret = 3;

  } else if ((*p & 0xf8) == 0xf0 && (*p < 0xf5)) {

    if (len < 4)

      return -1;

    if (((p[1] & 0xc0) != 0x80) ||

        ((p[2] & 0xc0) != 0x80) ||

        ((p[3] & 0xc0) != 0x80))

      return -3;

    value = ((unsigned long)(*p++ & 0x7)) << 18;

    value |= (*p++ & 0x3f) << 12;

    value |= (*p++ & 0x3f) << 6;

    value |= *p++ & 0x3f;

    if (value < 0x10000)

      return -4;

    if (value > UNICODE_MAX)

      return -2;

    ret = 4;

  } else

    return -2;

  *val = value;

  return ret;

}

/* This takes a Unicode code point 'value' and writes its UTF-8 encoded form

 * in 'str' where 'str' is a buffer of at least length 'len'.  If 'str'

 * is NULL, then nothing is written and just the return code is determined.

 * Returns less than zero on error:

 *  -1 if 'str' is not NULL and 'len' is too small

 *  -2 if 'value' is an invalid character (surrogate or out-of-range)

 *

 * Otherwise, returns the number of bytes in 'value's encoded form

 * (i.e., the number of bytes written to 'str' when it's not NULL).

 *

 * It will need at most 4 characters.

 */

int

UTF8_putc(unsigned char *str, int len, unsigned long value)

{

  if (value < 0x80) {

    if (str != NULL) {

      if (len < 1)

        return -1;

      str[0] = (unsigned char)value;

    }

    return 1;

  }

  if (value < 0x800) {

    if (str != NULL) {

      if (len < 2)

        return -1;

      str[0] = (unsigned char)(((value >> 6) & 0x1f) | 0xc0);

      str[1] = (unsigned char)((value & 0x3f) | 0x80);

    }

    return 2;

  }

  if (value < 0x10000) {

    if (UNICODE_IS_SURROGATE(value))

      return -2;

    if (str != NULL) {

      if (len < 3)

        return -1;

      str[0] = (unsigned char)(((value >> 12) & 0xf) | 0xe0);

      str[1] = (unsigned char)(((value >> 6) & 0x3f) | 0x80);

      str[2] = (unsigned char)((value & 0x3f) | 0x80);

    }

    return 3;

  }

  if (value <= UNICODE_MAX) {

    if (str != NULL) {

      if (len < 4)

        return -1;

      str[0] = (unsigned char)(((value >> 18) & 0x7) | 0xf0);

      str[1] = (unsigned char)(((value >> 12) & 0x3f) | 0x80);

      str[2] = (unsigned char)(((value >> 6) & 0x3f) | 0x80);

      str[3] = (unsigned char)((value & 0x3f) | 0x80);

    }

    return 4;

  }

  return -2;

}